1. Technical Field
The present invention relates generally to workpiece positioning apparatuses and, in particular, to positioning apparatuses capable of supporting workpieces being processed, trimmed, drilled, milled, and/or inspected.
2. Description of the Related Art
Manufacturing systems often include a holder and a machining tool for machining a workpiece held by the holder. It may be necessary to machine workpieces (e.g., aircraft panels, fuselages, airfoil skins, engine housings, or other structures) that have complex geometries. Traditional holders often have a set of vertically extendable modules capable of assuming different configurations such that the modules cooperate to support a workpiece. The modules may travel horizontally along rails to different locations underneath a workpiece. Unfortunately, complicated drive apparatuses are used to move these modules along the rails. These complicated drive apparatuses often require significant amounts of user training, frequent maintenance, recalibration, and expensive controllers. Additionally, it may be difficult or impossible to increase or decrease the number of modules mounted on the rails if the drive apparatuses are specifically designed for a fixed number of modules, thereby limiting manufacturing flexibility. Accordingly, these types of manufacturing systems may be unsuitable for machining structures commonly used in many industries, such as the aerospace industry.
Header board fixture apparatuses are often used to support relatively large workpieces, such as aircraft panels. An array of stationary or movable fixed height header boards can be support by a pair of horizontal rails. These types of header board fixture apparatuses may not be suitable for processing workpieces with different geometries, especially large curved workpieces (e.g., a portion of a fuselage) with complex geometries. Accordingly, fixed height header boards may be frequently replaced with header boards having different heights or repeatedly repositioned to process different workpieces resulting in significant maching down time and lost productivity.